In recent years, the demand for a liquid crystal display device has increased in association with the development of a personal computer, especially a portable personal computer. In addition, the market of liquid crystal display device has recently expanded more and more as the ownership rate of the household liquid crystal television has also increased and a smartphone and a tablet terminal have been widely spread.
Such a liquid crystal display device generally includes a liquid crystal cell unit equipped with a color filter, a counter substrate and a liquid crystal layer sandwiched therebetween and further a light source called backlight.
In recent years, a liquid crystal display device is strongly required to have a power saving function. In addition, a liquid crystal display device is required to have higher display quality, specifically, high contrast and high color reproducibility.
To cope with the requests for a liquid crystal display device describe above, for example, it has been investigated to use a white LED light source instead of a light source using a cold-cathode tube of the related art in the backlight, and the proposal has been partially put to practical use. The white LED light source has advantages such as a long life, high efficiency and power saving.
As the white LED light source; those having an aspect in which a blue LED and a yellow fluorescent substance are combined have been put to practical use, but those having an aspect in which a blue LED, a red fluorescent substance and a green fluorescent substance are combined are required from the viewpoint of high color rendering property and color reproducibility of liquid crystal display (Japanese Patent Application Laid-open (JP-A) No. 2010-093132). In addition, it is disclosed in JP-A No. 2010-093132 that it is possible to obtain a semiconductor light emitting device capable of imparting favorable color reproducibility in a case in which a fluorescent substance using Mn4+ doped K2MF6 (M=Si, Ge or Ti) as a red fluorescent substance and Eu-doped β-sialon fluorescent substance as a green fluorescent substance are used as the backlight source of a liquid crystal display device.
In addition, for example, the color filter is required to have higher brightness in order to increase the utilization efficiency of the backlight. It is disclosed, for example, in JP-A No. 2008-004766, JP-A No. 2011-007847, WO 2009/107734; JP-A No. 2013-057053, and JP-A No. 2013-242522 that the use of a blue color material constituted by a triarylmethane-based compound makes it possible to increase the transmittance of the blue coloring layer. In addition, it is known that it is possible to increase the transmittance of the green coloring layer by the use of a triarylmethane-based compound or the Pigment Green (hereinafter, abbreviated as PG) 1, PG7, PG36 and PG58 that are classified into the pigment in color index (C.I.; published by The Society of Dyers and Colourists) as the green color material. In addition, it is known that it is possible to increase the transmittance of the red coloring layer by the use of the Pigment Red (hereinafter, abbreviated as PR149, PR177, PR179, PR202, PR207, PR209, PR214, PR242, PR254, PR255 and PR264 and the Pigment Orange 38 as the red color material.